1. Field of the Invention
The invention relates to an integrated circuit socket assembly, more particularly to a zero insert-force integrated circuit socket assembly and to a conductive terminal pin therefor.
2. Description of the Related Art
Referring to FIG. 1, a conventional socket assembly for an integrated circuit, such as a central processing unit (CPU), is shown to comprise a chip mounting plate 11, a base body 12 and an actuating lever 13. The base body 12 is formed with a plurality of terminal holes 121 that receive a respective conductive terminal pin 14 therein. The chip mounting plate 11 is mounted slidably on the base body 12 and is formed with a plurality of through-holes 111 which permit extension of the pins of the integrated circuit (not shown) into a respective one of the terminal holes 121 in the base body 12. The actuating lever 13 is associated operably with the chip mounting plate 11 and the base body 12 and is operable so as to move the chip mounting plate 11 slidably on the base body 12 to make or break electrical connection between the pins of the integrated circuit and the conductive terminal pins 14 in the terminal holes 121. The actuating lever 13 is a generally L-shaped member with a first portion 131 that is operable manually to rotate the actuating lever 13, and a second portion 133 that is transverse to the first portion 131 and that is received pivotally in a pivot groove 122 formed in a top surface of the base body 12. The second portion 133 of the actuating lever 13 has a cam section 132 which engages a retaining groove 112 that is formed in a bottom surface of the chip mounting plate 11.
Referring to FIG. 2, each conductive terminal pin 14 includes a flat intermediate portion 141, a vertical head portion 143 having a lower end connected to the flat intermediate portion 141 by a bend 142, a contact portion 145 connected transversely to an upper end of the vertical head portion 143 by a bend 144, and a vertical mounting leg portion 146 extending downwardly from the flat intermediate portion 141.
Referring once more to FIG. 1, the conductive terminal pins 14 are mass-produced in the form of a stamped metal sheet. A connecting belt 15 interconnects the distal top ends of the conductive terminal pins 14 such that the distance between two adjacent conductive terminal pins 14 is about 2.54 mm, which is the distance between adjacent pins of the CPU, thereby facilitating the mounting of one row of conductive terminal pins 14 in the terminal holes 121 of the base body 12. The connecting belt 15 is torn off once the conductive terminal pins 14 have been mounted in the base body 12.
Referring to FIGS. 1 and 3, when the pins 18 of the integrated circuit are extended into the terminal holes 121 of the base body 12, the pins 18 are disposed initially between the vertical head portion 143 of the respective conductive terminal pin 14 and one of the side walls which confine the respective terminal hole 121. Since the conductive terminal pins 14 do not contact the pins 18 at this time, no resistance is encountered when the pins 18 are extended into the terminal holes 121. When the actuating lever 13 is operated so as to move the chip mounting plate 11 slidably on the base body 12, the pins 18 are moved toward the contact portion 145 of the respective conductive terminal pin 14 to establish electrical connection therewith. The contact portion 145 of the conductive terminal pins 14 press tightly the corresponding pin 18 toward one of the side walls which confine the respective terminal hole 121 to mount securely the integrated circuit to the base body 12.
It is noted that the aforementioned conventional conductive terminal pin 14 has a simple structure and can be conveniently mounted in the base body 12 of the socket assembly. However, the conductive terminal pins 14 are not mounted securely in the base body 12 since the former rely solely on the engagement between a diverging top end 147 of the vertical mounting leg portion 146 and the base body 12 to retain the same in the terminal holes 121.
FIG. 4 illustrates another conventional conductive terminal pin for a zero-insert force integrated circuit socket assembly. As shown, the conductive terminal pin 2 is similarly made from a stamped metal sheet and includes a contact portion 22 formed on a top end of a mounting leg portion 21. The contact portion 22 defines an upright pin receiving channel with an outer, wider channel section 201 and an inner, narrower channel section 202 communicated with the wider channel section 201.
The conventional conductive terminal pin 2 shown in FIG. 4 is capable of providing a greater pin retaining force than the conventional conductive terminal pin 14 shown in FIG. 2. However, since the total width of the conductive terminal pin 2 prior to bending of the stamped metal sheet (not shown) exceeds the standard 2.54 mm distance between adjacent pins of the CPU, one row of terminal holes in the base body of the integrated circuit socket assembly cannot be filled with the conductive terminal pins 2 in a single mounting operation, thereby inconveniencing the manufacture of the socket assembly. In addition, as with the conventional conductive terminal pin 14, the conductive terminal pins 2 are not mounted securely in the base body of the socket assembly since the former also rely solely on the engagement between a diverging top end 25 of the mounting leg portion 21 and the base body to retain the same in the terminal holes.